Data and pilot combining for composite GNSS signal acquisition

With the advent of new global navigation satellite systems (GNSS), such as the European Galileo, the Chinese Compass and the modernized GPS, the presence of new modulations allows the use of special techniques specifically tailored to acquire and track the new signals. Of particular interest are the new composite GNSS signals that will consist of two different components, the data and pilot channels. Two strategies for the joint acquisition of the data and pilot components are compared. The first technique, noncoherent combining, is fromthe literature and it is used as a comparison term, whereas the analysis of the second one, coherent combining with sign recovery, represents the innovative contribution of this paper. Although the analysis is developed with respect to the Galileo E1 Open Service (OS) modulation, the obtained results are general and can be applied to other GNSS signals

Galileo open service and weak signal acquisition

This paper describes the modifications in the GNSS acquisition systems due to the introduction of the BOC modulation in the Galileo signal

Galileo open service and weak signal acquisition

This paper describes the modifications in the GNSS acquisition systems due to the introduction of the BOC modulation in the Galileo signals

DTFT-based frequency lock loop for GNSS applications

A frequency lock loop (FLL) for Global Navigation Satellite System (GNSS) applications is described here. The core element is the discrete time Fourier transform (DTFT), that leads to a maximum likelihood (ML) frequency estimation and can be conveniently implemented in a software defined radio (SDR) HW platform. The algorithm is based on the iterative evaluation of DTFTs in a single frequency until the incoming frequency is locke

Impact and Detection of GNSS Jammers on Consumer Grade Satellite Navigation Receivers

Jamming is the act of intentionally directing powerful electromagnetic waves toward a victim receiver with the ultimate goal of denying its operations. This paper describes the main types of Global Navigation Satellite System (GNSS) jammers and reviews their impact on GNSS receivers. A survey of state-of-the-art methods for jamming detection is also provided. Different detection approaches are investigated with respect to the receiver stage where they can be implemented.JRC.G.5-Security technology assessmen

DTFT-based frequency lock loop for GNSS applications

Precise frequency estimation is one of the most stringent constraints for Global Navigation Satellite System (GNSS) receivers, that generally uses a Frequency Locked Loop (FLL) to provide a reliable evaluation of the Doppler frequency of the received signal. The proposed FLL is a two step algorithm based on an initial coarse estimation followed by an iterative procedure providing frequency refinements. The coarse estimation stage is implemented by finding the sampled frequency that maximizes the envelop of the FFT of a windowed portion of the input signal. The iterative procedure is based on the phase difference of two Discrete Time Fourier Transforms (DTFTs) evaluated over two overlapping data segments at the previous frequency estimate. The FLL has been integrated with denoising blocks, and median filters have been added to reduce the effect of outliers in the frequency estimation: simulations have proved the effectiveness of the system and the obtained results are very encouraging and show the feasibility of an FLL based on DTFT